Overexpression of phospholipid: diacylglycerol acyltransferase in Brassica napus results in changes in lipid metabolism and oil accumulation.
Overexpression of phospholipid: diacylglycerol acyltransferase in Brassica napus results in changes in lipid metabolism and oil accumulation.
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DOI：
10.1042/bcj20220003
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发表时间：
2022-03-31
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油料种子中脂质代谢的调节仍然没有完全理解，增加我们在这方面的知识具有重要的经济和智力意义。油菜（Brassica napus）是一种主要的全球性油料作物，其中三酰甘油（TAG）积累的增加已经通过相关生物合成酶的过表达来实现。在这项研究中，我们表达拟南芥磷脂：二酰基甘油酰基转移酶（PDAT 1），其中的两个主要TAG形成植物酶在B。以DH 12075为材料，研究了其对种子发育过程中脂类代谢的影响，并估算了其通量控制系数。尽管PDAT活性增加了几倍，但三个独立产生的PDAT转基因事件的种子显示出种子油含量的小而一致的减少，并且改变了磷酸甘油酯和TAG的脂肪酸组成，朝向更少的不饱和度。种子切片的质谱成像证实了脂质成分的变化，并表明PDAT过表达改变了磷脂酰胆碱（PC）分子种类的明显异质性分布。观察到TAG分子种类分布的类似但不太明显的变化。我们的数据表明，PDAT对TAG生物合成施加了一个小的、负的通量控制，并且在B的微调中可能具有未被充分认识的作用。油菜种子脂质组合物以组织特异性的方式。这对增加类似作物中石油积累的努力具有重要意义。
The regulation of lipid metabolism in oil seeds is still not fully understood and increasing our knowledge in this regard is of great economic, as well as intellectual, importance. Oilseed rape (Brassica napus) is a major global oil crop where increases in triacylglycerol (TAG) accumulation have been achieved by overexpression of relevant biosynthetic enzymes. In this study, we expressed Arabidopsis phospholipid: diacylglycerol acyltransferase (PDAT1), one of the two major TAG-forming plant enzymes in B. napus DH12075 to evaluate its effect on lipid metabolism in developing seeds and to estimate its flux control coefficient. Despite several-fold increase in PDAT activity, seeds of three independently generated PDAT transgenic events showed a small but consistent decrease in seed oil content and had altered fatty acid composition of phosphoglycerides and TAG, towards less unsaturation. Mass spectrometry imaging of seed sections confirmed the shift in lipid compositions and indicated that PDAT overexpression altered the distinct heterogeneous distributions of phosphatidylcholine (PC) molecular species. Similar, but less pronounced, changes in TAG molecular species distributions were observed. Our data indicate that PDAT exerts a small, negative, flux control on TAG biosynthesis and could have under-appreciated effects in fine-tuning of B. napus seed lipid composition in a tissue-specific manner. This has important implications for efforts to increase oil accumulation in similar crops.